Recently, during the automatic machine recognition and automatic transaction processing of bank checks printed with magnetic ink characters and the information on other payment media, since the magnetic ink character has advantages of strict printing specifications, being convenient for the device recognition and reading and manual recognition and reading and so on, the magnetic ink character recognition (abbreviated as MICR) technology has been widely applied in the bank field and other payment fields.
For example, in the prior art, an image scanning method employing an optical scanning apparatus can be used to automatically recognize the information on bank checks or other payment medium (such as images obtained by CIS and CCD), however, when on the medium there are stained characters or missed characters or the concentration of the printing characters grow thinner, the quality of the scanned image will decline obviously, and when optical character recognition (such as OCR recognition and so on) is performed on the information, the recognition rate of the characters will decline due to the decline of the quality of the original scanned image. Since the effect on the magnetic signal due to stained characters, missed characters, printing characters being uneven in concentration and the like on the medium is little, performing character recognition using magnetic ink character magnetic signal can effectively improve the recognition rate of the characters and reduce the effect on the character recognition stability caused by the decline of the quality of the magnetic ink character image on the medium.
The process of character recognition of the magnetic ink signal is as follows: first, reading a magnetic string formed by a plurality of characters representing check number or other information printed on the medium using a magnetic head, generating a corresponding magnetic string signal, and then performing positioning, segmenting, character extraction and character recognition on the magnetic string signal. Although, performing recognition using the magnetic properties of the magnetic signal can improve the character recognition rate, the magnetic character recognition rates of different magnetic character recognition methods are also different, and the requirements on the stability of the magnetic signal are also different, and the requirements on the stability of the magnetic signal by the current magnetic character recognition method are relatively high.
For example, American patent US2007/0267495 proposes a character recognition method using the amplitude features after Fourier transform of the magnetic signal, in which in order to reduce the effect on the recognition rate by the significant change of the amplitude of the signal, this method has to normalize the amplitude characteristic vector of the original signal for Fourier transform before matching and recognition so as to avoid some effective features being covered by the noise interference in the signal and then directly matches the extracted amplitude features with the amplitude template of each character in the template library and selects the template character with the closest amplitude feature as the recognition character, however, since normalization cannot well effectively overcome the effect on character recognition by the significant change of the amplitude caused by the magnetic signal due to external noise interference, this method puts high requirements on the stability of the original magnetic signal, and comparison recognition is performed using the amplitude size of the amplitude feature, and the character recognition rate declines obviously when the external interference causes the amplitudes of different characters to change significantly.
There is still no effective solution proposed regarding the problem in the related art that the character recognition rate declines when the amplitude of the magnetic ink character signal varies significantly.